The impact of non-specific low back pain is very significant. There are a multitude of factors which are beginning to be identified as contributing to the cause of low back pain. It is a well documented fact that back problems are one of the most costly elements at this time.
The majority of patients with back pain do not display clinical symptoms. Rather, their pain is related to non-specific or mechanical causes. The identification of work place and individual risk factors, including the development of appropriate preventive programs is an acknowledged need. Contemporary viewpoints concerning treatments are shifting from the traditional medical model of care to preventive and maintainance oriented programs organized and run at the work site. Understandably, this new emphasis has led to the need to develop more sensitive evaluation tools.
The loss of ability to freely extend the lumbar spine has been cited by numerous investigators as being associated with non-specific low back pain. Thus, there is a need for a definitive biomedical dependent measure to quantify this observed association.
Disclosed in U.S. Pat. No. 4,485,825 (Domjan et al) is an instrument for measuring displacements of joints and the spinal column. The instrument consists of a combination of a dip-circle (inclinometer) and a compass which are used to measure vertical and horizontal displacements, respectively. Measurements of the spine can be made by using four of these devices attached a various locations along the spine.
Another method of measuring the end range extension of the lumbar spine is known as the Cureton test. This test was designed to measure the flexibility of athletes. According to the method, the subject first lies prone on a table with his feet held down and his hips in firm contact with the table. The subject next raises his trunk as far backward as possible. The Examiner then measures the vertical distance from the suprasternale to the top of the table. This measurement is then multiplied by 100, and the product divided by the trunk length. The measurement of trunk length is made with the subject seated on a bench with his back flat against a wall. The vertical distance between the suprasternale and the bench is then determined. During this measurement, the subject is instructed not to make any effort to raise his chest, but merely to direct his head up moderately.
Other general devices in the prior art for measuring bone structure or body measurements of a patient have been disclosed. Example of these devices are disclosed in U.S. Pat. No. 3,575,159 (Pile et al) and U.S. Pat. No. 4,135,498 (McGee).
Although there is now a recognized need to provide a measurement of the end range extension of the lumbar spine, none of the above devices disclosed in the prior art provide a simple and efficient measurement of this extension which is easily read and easily repeated.